The present invention relates generally to locking devices for connectors, and particularly to a means of securing an implantable lead in a stack of electrical connectors, particularly for an implantable medical device, with a threaded seal latch using a ferrule or molded bead feature, collectively or individually otherwise referred to as an enlarged member or section located on a lead.
Generally, connecting a lead to an implantable medical device involves the use of an additional set screw to restrain the lead, if not to facilitate the connection altogether. To achieve connecting and locking of the lead, the prior art typically involves the use of a set screw that is screwed into an additional hole threaded radially to an axis of insertion within the implantable device header that holds the lead in the medical device. The inserted set screw radially engages the side of the lead, applying a force or mechanical interference between the end of the screw and the lead, thereby securing the position of the lead within the medical device.
However, in these devices, after only a few insertions and removals of the set screw, metal shavings from the threaded portions can enter the lead cavity or spread out into the human body, leading to contamination and possibly complications. In addition, once the set screw is inserted into these devices, there is no opportunity for visual inspection, and there is no way to ensure that the connection is secure. Furthermore, the set screw hole is an additional potential leakage source for body fluids to enter the medical device. The set screw assembly must be sealed with silicone filler once the screw is inserted to prevent leakage, and removal of the set screw requires removal of the filler. Additionally, the set screw can become accidentally disconnected from the device during surgery and can be lost in the body. Finally, the set screw requires a tool to operate and thereby increases the complexity of the device or at least requires additional steps during surgery.
Connectors having multiple in-line contacts, such as audio plugs, can also benefit from improved securing means.